Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0278080 (physical dependence)
 1,658 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The self-administration of D-enkephalin was studied in the dependent rat self-administering morphine. The rats were prepared with chronic IV and bilateral intraventricular (IVT) injection cannulae. They were made physically dependent on morphine and trained to lever press for IV morphine self-injections (inj) (10 mg/kg) on a fixed ratio (20) (FR20) schedule of reinforcement. Substitution of D-enkephalin either IVT (40 microgram/inj) or IV (10 mg/kg/inj) in the morphine-dependent rat maintained consistent lever pressing and self-administration behavior similar to morphine self-administration. No signs of abstinence were observed during the D-enkephalin substitution. However, saline substitution (0.05 ml/inj IV) for morphine in the self-administering rat produced an abstinence syndrome characterized by extinction of responding, wet-dog shakes, writhes, and diarrhea, which were reversed for 1 h by a single IVT injection of D-enkephalin (40 or 80 microgram). These results indicate that D-enkephalin will serve as a reinforcer to maintain opiate-seeking behavior and support physical dependence in the rat.
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PMID:D-ala2-methionine-enkephalinamide self-administration in the morphine-dependent rat. 677 7

The purpose of the present paper is to investigate the effect of combined treatment of morphine and ethanol on preference for morphine or ethanol and morphine dependence formation. Rats were treated with morphine by DAF (drug-admixed food; 0.5 and 1 mg/g food) method or subcutaneous injection (20-100 mg/kg body weight), and/or treated with ethanol solution (5 and 10 w/w %) or oral administration (2.5 g/kg body weight). There were no effects of chronic treatment of ethanol and morphine on preference for morphine and ethanol, respectively. While, preference for morphine did not increase and preference for ethanol enhanced markedly in rats chronically treated with morphine and ethanol. Effect of chronic ethanol treatment on morphine physical dependence formation in rats was evaluated by body weight loss after morphine withdrawal, and the weight loss significantly attenuated and diarrhea was suppressed in comparison with morphine alone group. These results indicated that preference for morphine and morphine physical dependence formation were reduced when rats were chronically treated with ethanol during chronic morphine treatment, and that preference for ethanol was enhanced.
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PMID:[Effects of combined administration of morphine and ethanol on drug selecting behaviors and the development of drug dependence]. 689 49

We examined the locomotor-enhancing action of mu-opioid receptor agonists, such as morphine and [D-Ala2, N-MePhe4, Gly-ol5]enkephalin (DAMGO), and physical dependence on morphine in diabetic and nondiabetic mice. Morphine (5-20 mg/kg, s.c.) and DAMGO (1-4 nmol, i.c.v.) had a dose-dependent locomotor-enhancing effect in both nondiabetic and diabetic mice. The locomotor-enhancing effects of morphine and DAMGO were significantly less in diabetic mice than in nondiabetic mice, and were significantly reduced after pretreatment with either beta-funaltrexamine (20 mg/kg, s.c.), a selective mu-opioid receptor antagonist, or naloxonazine (35 mg/kg, s.c.), a selective mu1-opioid receptor antagonist. Both diabetic and nondiabetic mice were chronically treated with morphine (8-45 mg/kg, s.c.) for 5 days. During this treatment, neither diabetic nor nondiabetic mice showed any signs of toxicity. After morphine treatment, withdrawal was precipitated by injection of naloxone (0.3-10 mg/kg, s.c.). Several withdrawal signs, such as weight loss, diarrhea, ptosis, jumping and body shakes, were observed after naloxone challenge in morphine-dependent nondiabetic mice. Although morphine-dependent diabetic mice showed greater weight loss than nondiabetic mice, the incidence of jumping and body shakes after naloxone challenge in diabetic mice were lower than that in nondiabetic mice. These results suggest that diabetic mice are selectively hyporesponsive to mu1-opioid receptor-mediated locomotor enhancement. Furthermore, diabetes may affect mu1-opioid receptor-mediated naloxone-precipitated signs of withdrawal from physical dependence on morphine.
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PMID:Modification of mu-opioid agonist-induced locomotor activity and development of morphine dependence by diabetes. 763 31

The destruction of N-methyl-D-aspartate (NMDA) receptor-bearing neurons by insulin-induced hypoglycemia has long been known to be due to excessively released aspartate and glutamate. In this study, the effects of NMDA-bearing neuron destruction by insulin-induced hypoglycemia on the development of morphine (M) physical dependence, which was found related to functional states of NMDA receptors, were investigated. NMDA receptor antagonists CGP 39551 and MK-801 were used to see whether they could change intensity of precipitated abstinence syndrome by preventing destruction. Therefore, two groups of fasting rats injected IP with physiological saline, and another two groups given IP 10 mg/kg CGP 39551 and 0.5 mg/kg MK-801 received 15 IU/kg crystalline zinc insulin IP. After 2 h, the rats were orally given 2 x 4 ml of 5% glucose solution. On the third day, two pellets containing 75 mg base M were SC implanted to all rats. On the sixth day, they were IP given 2 mg/kg naloxone (NL). Then jumps, wet-dog shakes, and defecation were counted while diarrhea and ptosis were rated for 15 min. The rats given insulin manifested significantly more intense NL-precipitated abstinence syndrome than controls. The rats administered CGP 39551 showed a less intense physical dependence than those injected with only insulin. But, the intensity was still significantly higher than controls. In the rats that received MK-801, the abstinence syndrome was more or less equal to that in controls.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Morphine physical dependence intensification by hypoglycemia: NMDA receptor involvement. 793 7

The new cognition-enhancing agent nefiracetam (N-(2,6-dimethylphenyl)-2-(2-oxo-1-pyrrolidinyl) acetamide, DM-9384, CAS 77191-36-7) was assessed for dependence liability in rats using the DAF (drug admixed food) method and an intravenous self-administration system. In the physical dependence test, nefiracetam and codeine phosphate were administered to rats mixed with food for 43 days in a gradually increasing dosage schedule, followed by feeding a drug-free normal diet to detect signs of withdrawal. After the withdrawal, rats in the nefiracetam treated groups showed no withdrawal symptoms (e.g. body weight loss) and exhibited greater body weight gains than control. On the other hand, rats in the codeine phosphate treated group showed overt withdrawal symptoms (e. g. soft stool, diarrhea, vocalization) and a significant body weight loss, suggesting development of physical dependence on the drug. It was concluded that nefiracetam did not possess physical dependence liability in rats. In the reinforcement liability test, through an indwelling cannula implanted into the right jugular vein rats were allowed to self-administer nefiracetam, morphine hydrochloride or pentobarbital for 14 days. Saline was administered to negative control animals for the same period. The daily frequency of self-administration increased progressively with time in rats of the morphine hydrochloride and pentobarbital groups. In the nefiracetam groups, it remained comparable to or was even lower than that in the saline control group. When compared with the saline control, the group mean frequency of self-administration showed a tendency to be small for nefiracetam, whereas the morphine hydrochloride and pentobarbital showed greater frequencies.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Drug dependence study of the new cognition-enhancing agent nefiracetam in rats. 801 97

Previously, we have shown that the development of physical dependence on morphine in mice is inhibited substantially by treatment of mice with the highly selective, nonequilibrium delta-2 opioid receptor antagonist, naltrindole-5'-isothiocyanate. With the availability of the highly selective, nonequilibrium delta-1 opioid receptor antagonist, [D-Ala2,Leu5,Cys6]enkephalin, it was possible, in the present report, to examine the possible involvement of delta-1 opioid receptors in the development of opiate dependence. Mice were made physically dependent on morphine by s.c. implantation of morphine pellets (75-mg free base) for 3 days. The degree of dependence was quantified by determining the ED50 values of naloxone to precipitate withdrawal jumping and diarrhea. Neither sign of opiate withdrawal was affected by chronic treatment of animals with [D-Ala2,Leu5,Cys6]enkephalin during the morphine implant period. The data suggest that delta-1, as opposed to delta-2, opioid receptors are not involved in the development of physical dependence on morphine. This fact takes on added significance because the recently cloned delta opioid receptors appear to be the delta-2 subtype and the present data together with previous findings suggest that the cloned receptors may be proper models for the study of opiate dependence.
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PMID:Lack of involvement of delta-1 opioid receptors in the development of physical dependence on morphine in mice. 803 33

The possible involvement of delta 2 opioid receptors in the development of morphine dependence was investigated using selective delta 2 receptor antagonists, naltriben (NTB) and naltrindole 5'-isothiocyanate (5'-NTII). The degree of morphine dependence was estimated by the ED50 values of naloxone (s.c.) required to precipitate withdrawal jumping and diarrhea 72 hr after morphine pellet implantation. NTB administered s.c. as well as naloxone precipitated jumping and diarrhea in morphine-dependent mice. Chronic treatment with 5'-NTII (both i.c.v. and i.t. routes, 24 hr before, just before, 24 and 48 hr after morphine pellet implantation) increased the ED50 values of naloxone for jumping and diarrhea. These results suggest that both supraspinal and spinal delta 2 opioid receptors are involved in the development of physical dependence on systemically administered morphine. However, chronic treatment with NTB (s.c. route, 30 min before, 24 and 48 hr after morphine pellet implantation) failed to affect the ED50 values of naloxone for both withdrawal signs. These seemingly discrepant results suggest that continuous blockade of delta 2 opioid receptors (by a nonequilibrium and long-lasting antagonist, 5'-NTII) rather than intermittent blockade of delta 2 opioid receptors (by an equilibrium and relatively short-acting antagonist, NTB) is necessary to inhibit the development of morphine dependence.
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PMID:Involvement of delta 2 opioid receptors in the development of morphine dependence in mice. 838 38

Pregnant rats were SC injected with physiological saline (control) or 10 mg/kg morphine (morphine group) or 2 mg/kg naloxone (naloxone group) three times daily during the last 5 days of gestation. Three weeks after birth, male young rats of each group were taken and placed in separate cages. When their body weight reached 130-150 g, 10 rats from control, morphine, and naloxone groups were SC implanted with two pellets containing 75 mg morphine base (total 150 mg). Three days following implantation, rats were IP given 2 mg/kg naloxone for precipitated abstinence syndrome. Immediately after naloxone injection, rats were strictly observed for 15 min and jumping, wet-dog shakes, teeth-chattering, diarrhoea, defecation, and ptosis counted or rated. All abstinence syndrome signs were significantly higher in the morphine or naloxone group than in control. On the basis of the previous experimental findings supporting the idea that opiate physical dependence is related to the binding of opiate, possibly other than their own, to NMDA receptors and the upregulation and/or supersensitivity associated with the binding, the intensification of morphine dependence has been attributed to the long-lasting NMDA receptor upregulation and/or supersensitivity.
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PMID:Prenatal exposure to morphine or naloxone intensifies morphine dependence at maturity. 846 3

The severity of naloxone-precipitated withdrawal in rats infused intravenously with morphine at the rates of 2.5, 5 and 10 mg/kg/hr over various time periods was investigated. Plasma morphine concentration reached a constant and rate-dependent level at 1 hr after the start of morphine infusion, and this level was maintained until the termination of infusion. Naloxone (2.0 mg/kg, s.c.) was challenged 18 hr after infusion was stopped, and the withdrawal was evaluated by plasma corticosterone (PCS) increase, diarrhea and body weight loss. The incidence of naloxone-precipitated withdrawal signs was related to both the infusion rate and duration of morphine infusion. The duration of morphine infusion (ET50) needed to elicit naloxone-precipitated PCS increase and diarrhea in 50% of the rats was inversely related to the morphine infusion rates, but the total amount of infused morphine (EA50) that elicited naloxone-precipitated withdrawals in 50% of rats was the same at all infusion rates. These results suggest that the total amount of morphine infused may play an important role in the development of acute physical dependence on morphine rendered by continuous intravenous morphine infusion for 1-8 hr.
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PMID:Possible involvement of the total amount of morphine infused in the development of acute morphine dependence in rats. 882 85

Repeated intracerebroventricular injections of antisense oligodeoxynucleotides (ODNs) were used to selectively restrict the expression of cloned mu and delta opioid receptors (OR) in the mouse brain. Reduction of mu and delta OR-like immunoreactivity was observed in brain structures of experimental mice. A random-sequence ODN used as a control showed no effect. ODNs to OR decreased radiolabeling of neural structures after intracerebroventricular injection of 125I-immunoglobulins G directed to mu or delta OR. The potencies of opioids binding the mu OR, [D-Ala2,N-MePhe4,Gly-ol5]enkephalin and morphine were significantly attenuated in mice injected with ODNs to this receptor, an effect not seen for the delta OR-binding agonists, [D-Pen2,5]enkephalin and [D-Ala2]deltorphin II. In morphine-dependent mice, ODNs to mu OR reduced the incidence of naloxone-precipitated withdrawal jumping, body weight loss and diarrhea. The ODN directed to nucleotides 7-26 of the delta OR mRNA selectively impaired antinociception induced by [D-Ala2]deltorphin II (delta-2), but not that of [D-Pen2,5]enkephalin (delta-1) or morphine. It also diminished the incidence of withdrawal signs precipitated by naloxone in morphine-dependent mice. Thus, the cloned mu OR mediates morphine-evoked antinociception as well as physical dependence. The involvement of delta-2 OR in the development and/or expression of morphine dependence is suggested.
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PMID:Antisense oligodeoxynucleotides to opioid mu and delta receptors reduced morphine dependence in mice: role of delta-2 opioid receptors. 906 32


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